Protein instability in white wines: Mechanism of formation and methods for predicting it

Protein haze can appear in white wines during transportation and storage.
This instability represents an aesthetic problem that can be prevented by removing the grape proteins that have survived the winemaking process.

The grape proteins responsible for this instability are the pathogenesis-related (PR) proteins, a class of proteins very stable during winemaking, but that can become unstable during ageing, especially when the wine is subjected to elevated temperatures during transport or storage.
This instability results in PR-proteins denaturation, and this in turn leads to their aggregation and precipitation, with formation of turbidity and sediments in bottled wines.

Winemakers are still widely using bentonite fining to remove these proteins from the wine. While effective, bentonite fining is an inefficient process that can lead to quality losses in the wine due to the removal of volatile compounds associated with its use. 

The development of more efficient processes for protein removal requires understanding the mechanisms such as the main drivers of protein instability and the impacts of various wine matrix components on haze formation.
Additionally, to improve the efficiency of stabilization treatments, accurate methods to predict protein instability are needed.
In this video Matteo Marangon reviews:

• The recent developments in wine protein instability, including the most current version of the mechanism describing how protein instability forms in white wines.
• The methods for wine protein stabilization
• The methods to predict protein instability in wines

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About the speaker: 
Matteo Marangon holds a MSc in Agricultural Sciences (2004) and a PhD in Enology (2008), both from the University of Padova (Italy). In 2008 he joined the Australian Wine Research Institute as a Research Scientist. In 2014 Matteo joined Plumpton College (UK) to lead a Master of Science in Viticulture & Oenology, before returning to the University of Padova in 2016, where he is now an Associate Professor and leads the MSc in “Italian Food and Wine”. Prior experience includes seven vintages as assistant winemaker in wineries of North-East of Italy. Matteo’s research is focussed on the study of wine stability and wine colloids, and on their effect on wine quality attributes. Matteo has authored 51 publications indexed in Scopus, is a reviewer for over 15 international scientific journals, and is regularly invited as keynote speaker in several international conferences.